An oscilloscope is an instrument for graphically displaying measured electrical parameters, such as voltage. Typically, an oscilloscope's graphical display includes a two-dimensional plot of the electrical parameter versus time.
Originally, oscilloscopes were analog devices, which displayed their graphics on a cathode ray tube (CRT). Newer types of oscilloscopes are digital. For example, a digital storage oscilloscope (DSO) can convert analog signals to digital form, store those signals, and process the signals for display, typically on a liquid crystal display (LCD) device.
DSOs typically use high-speed custom digital integrated circuits (ICs) to obtain high-speed triggering with complex, advanced triggering features. These ICs are often bipolar logic circuits rather than common, low-cost CMOS circuits. As a result, these ICs are expensive and consume relatively large amounts of power. Programmable logic typically does not enable triggering at the high speeds required by DSOs.